Drop by drop pump



Jan. 29, 1946. J. P. TARBOX DROP BY DROP PUMP Filed Nov. 10, 1943 3Sheets-Sheet 1 INVENTQR Jan. 29, 1946. J. P. TARBOX DROP BY DROP PUMP s Sheets-Shee t 2 Filed Nov. 10, 1943 INVENTOR Jan. 29, 1946. V R TAR 2,393,838

DROP BY DROP PUMP Filed Nov. 10, 1943 s Sheets-Sheet a INVENTOR Patented Jan. 29, 1946 DROP BY DROP PUMP John P. Tarbox, Philadelphia, r... assignor to Foundation for Clinical and Surgical Research," Philadelphia, 'Pa., a corporation of Pennsylvania Application November 10, 1943, Serial No. 509,735 8 Claims. (01.103-148) This invention relates to apparatus for sampling fluids.

In many fields in industry and in the arts and sciences, need frequently arises for the examination of samples of a fluid such as a chemical mixture or composition or, in the medical field,

closely defined limits and that the apparatus employed permit withdrawal in definitely small quantities as well as in larger amounts. For example, drop-by-drop extraction under complete control of the operator may be a matter of considerable importance in some medical, scientific or manufacturing operations.

Accordingly, one of the important objects of the present invention is to provide apparatus capable of drop-by-drop extraction from a source oi supply. Another object is to provide apparatus susceptible to close controi by the operator to vary the amount of fluidif withdrawal to any desired quantity as required. Further objects are directed to the provision of fluid withdrawal apparatus 01' extreme simplicity in the number and arrangement oi. parts: to the provision of apparatus susceptible to multiplied means of adjustment; to the provision oi. apparatus adapted to function with a limited amount 01' power; and to the provision of means in general readily applicable to a wide variety of extraction or sampling operations. Other ad- 4 vantages stemming from the structure of the apparatus will become apparent on consideration of the modifications of the invention hereinafter described and illustrated.

Referring to the drawings:

Figure 1 is a view of the apparatus associated with a fluid containing tube illustrating the phase wherein pressure in the tube is being released:

Figure 2 illustrates the apparatus in the phase of complete pressure release;

Figure 3 shows the apparatus in the first stage of pressure;

Figure 4 shows the apparatus under condition of full pressure;

Figure 5 illustrates a modification or the apparatus; and

Figure 6 is a detailed sectional view along lines 6-8 of Figure 5.

In Figure 1 the numeral. ll designates a tube reassume its normal state on release of the pressure. The inlet end or the tube ii is connected to the liquid supply, for example. where the device is employed in connection with liquids. The numeral l2 designates the outlet end of the tube from which liquid in the desired sampling lots is obtained. In the apparatus, as shown in Figure 1, the tube ill is mounted between supporting blocks l3, l4, l5 and it which by any appropriate means as screws I! are fixed to a base.

support. Support block I! is formed with slots ll. transverse relative to the tube so that the block may be moved relative to the supporting screws l9 and consequently in relation to the tube l0. In this manner, adjustment to tubes of different diameters may be made, since support block it is on one side or the tube, whereas blocks I4, I! and [8 are on the opposite side, the tube being placed between.

In addition to the supporting function 01' block it, it also serves as a support for a pressure block 20. This pressure block is formed with a rounded wedge-shaped end 2| adapted to contact and compress the tube In against the upper support block l8, thereby cutting iii! connection between the tube interior on either side or the pressure point, designated by b. The base 0! the pressure blockis secured to a pivot rod, 22 which is formed with two apertures, one, 28, in a form of an. axial slot adjacent the end of the rod removed from the support block 20 and the other aperture 24 adjacent the support block 20. Slot 23 is intended for the reception of a screw pivot 25 including the screw head 28 with associated washer 21, a degree of clearance being provided between.the washer 21 and the bar 22 so as to permit pivotal action of the bar on the screw thread. The aperture 24 is adapted to receive a screw 28 having a head 29, shank l0 and screw threaded end It adapted to penetrate the end of support block II at the ends of the block aiacent the support block 20. Two movable washers 32 on the screw shank 30 form terminal plates for an intervening coil spring 3!, the normal pressure 01 this spring being to force the bar 22 with the attached pressure block 20 into closure position with reference to the liquid carryin; tube ll. However, with the application oi. pressure from the tube through the-pressure block 20 in excess of the spring pressure, the spring 83 will yield to permit pivotal movement or the bar 32 on the pivot screw 25.

Support blocks I4, I! and II which are on the side of the tube opposite from the support block it, are spaced mm each other to receive operating mechanism which will now be described.

Between blocks l4 and I5 is a pressure block 40 having a wedge-shaped edge 46a transverse of and adjacent to the tube II and adapted to have movement toward and away from the tube to close the passage way through the tube at this point, designated as a. The top edge 01 the pressure block 40 is recessed and threaded to receive the threaded end of a bolt 4I carrying a head 42, slidable washers 43 and 44 and a coil spring 45 surrounding the shank of the bolt between the base edge of the support block 86 and the washer 44. The pressure block 46 is adapted for reciprocation to and away from the tube H I through the medium or a. lever 46 to which connection of the bolt M is made by insertion of the bolt shank in an aperture d1 formed in the lever arm 46 so that the lever arm is included between the washers 43 and 44. A coil spring 45 encloses the bolt 4i between the washer 44 and block 40.

The pivot lever end 46 is provided with spaced holes 48 through which a movable pivot bolt 59 is adapted for insertion. The other end of the lever is also provided with displaced apertures 56 in one of which is positioned a second fixed pivot pin or bolt 5!. The link 52 connects the pivot pin 5| to a stud 53 projecting from the face of the drum wheel 58. Rotation of the pulley wheel by means of the pulley rope 55 translates the rotational action to the pulley into oscillation of the lever 46 and consequent linear movement of the pressure block 40 whereby alternate closure oi. the tube at point a followed by opening of the same is secured. By adjustment of the pivot pin 5I with reference to the aperatures Bil the range of oscillation and tube closure may be varied. By adjustment of the lever pivot 48 i in the apertures 48 correct placement of the pressure block between the guide blocks I4 and I5 may be attained.

In addition to the pressure block bolt 4I there is secured to the lever arm 46 at a point adjacent thereto and between said bolt and pivot pin 5|, a second screw bolt 56 which penetrates the lever vertically with its head 51 on the same side as the head 42 of bolt H and its bearing end 58 on the other side of the lever. Lock nuts 59 are utilized on either side of the lever to hold the bolt 56 in a predetermined set position. The bearing nut 58 of bolt 56 is adapted for intermittent engagement with a power pressure block 60 which is mounted between the guide blocks I5 and I6 and is adapted for reciprocation between those blocks toward and away from the tube I0. As shown in Figure 1, the position of the block 60 is in inactive position with its lower edge surface resting on that of the tube and its upper edge surface displaced from the operating end 58 of the contact bolt 56. It is apparent that further rotation of the drum 54 in the direction indicated by the arrow will carry the lever arm upwardly removing the contact pin 56 still further from engagement with the power block 60 until it has the relative position as shown in Figure 2 with the stud pin 53 at the maximum peak point of its circular movement. In Fig. 1 also the pressure block 40 is above its closure point and the tube section a-b is fully extended and, in operation, filled with liquid. In the positions of Fig. l and Fig. 2 it is apparent that'the pressure of spring 33 on the guide screw 30 has forced the pressure block 26 to the upward limit of its movement, to form the 010- sure b, and liquid is thus retained in the section a-b pending further operation of the apparatus.

tube section a-b. Result of this pressure is to force liquid through the inlet at a, until the pressure block 40 reaches the lower limit of its movement. This provides a leakage path to reduce the capacity of the a--b tube section so that when the gap a closes the liquid in the ab section is of reduced amount. Further downward movement of block 60 after closure of a, forces out liquid at b, as shown in Figure 4, since the spring pressure of spring 33 is less than that due to spring 45. Consequently the measured quantity of liquid will pass to the exit side I2 of the tube III. Continued rotation of the drum 56 will produce intermittently further excretion of liquid in uniform quantities as desired, the sequences of inflow and outflow of liquid through the chamber a-b being indicated by the sequence of Figures 1, 2, 3 and 4. From the above it will be seen that by adjustment of bolt 4| or the angle of movement of lever 46 the quantity of liquid forced out at tube gap b may be varied at will.

In Figure 5 of the drawings, a modification of the invention is disclosed wherein the pressure block 20, instead of being pivotally mounted on the guide block I3 is positioned on the side common to the pressure block 40 and power block 66. In this arrangement a single support block I0 with transversely positioned slots II and holding screws I2 is placed beneath the tube III. The support blocks I4 and I5 are as shown in Figure 1 but in place of the block I6 of the Figure 1 is employed an L shaped block I3, the one end of the L 14 forming a guide area for the tube and the other end and associated segment 15 of the block forming a bracket overlying the pressure block I6 corresponding to the pressure block 20 of Figure 1. This block I6 is also provided with an operating tube-contacting edge of wedge shape and, on the opposite edge, a bridging pin I1 penetrating at its outer end an aperture formed in the overlying bracket section I5 of the support block 13. A coil spring I8 encircles the pin 11 between the bracket section 15 and the pressure block head 16 normally urging the head downwardly to form the closure d. The

lever arm with the associated parts are the same the invention as shown in Figure 1, it Was mentioned that the support blocks I4, I5 and I6 were secured to a supporting base. Similarly the support blocks I4, I5 and I3 of Figure 5 are attached to a supporting base as shown in Figure 6, this figure being-in general applicable to both modifications as showing the mode of attachment. In this figure, the base is indicated by the numeral 80 and the supporting blocks and pressure blocks are illustrated in relationship to this base.

It is pointed out thatonly a small upward movement of the block 40 is necessary to provide a gap in the tube opening a of area suflicient to fill the tube section ab rapidly. In other words, an up-movemen't of the block Ill when the pin 54 of the power drum is adjacent the maximum point of Fig. 2 maybe adequate for filling the tube section a-b.

Modifications other than as shown may be made not only in the specific structure but in the sequence ofv operation and hence no limitation of the invention is implied by the specific forms shown, the limits of the invention being determined by the claims as hereto appended.

What is claimed is:

1. Fluid transfer apparatus comprising a flexible tube for conducting a fluid, first means for 1 clomng yieldabl said tube at a predetermined point, second means for clomng yieldably said tube at a normally open and unrestricted point displaced from the first closure'point whereby fluid is trapped in the tube between said closure points, said first means being more readily yieldable than said second means, pressure means for pressing said tube between said closure points and means for actuating said second and pressure means intermittently whereby fluid is forced through said second closure means.

2. Fluid transfer apparatus comprising a flexible tube for conducting a fluid, first means for closing yleldably said tube at a predetermined point, second means for closing said tube at a point displaced from the first closure point whereby fluid is trapped in the tube between said closure points, and power pressure means for pressing said tube between said closure oints whereby fluid is forced through said yieldable closure, said power means including a pressure block in direct contact with said tube, a lever arm pivoted adjacent said block, and means for oscillating said lever intermittently into pressure engagement with said block.

3. Fluid transfer apparatus comprising a flexible tube for conducting a fluid, first means for closing yieldably said tube at a predetermined point, second means for closing said tube at a point displaced from the first closure point but subsequent to said first closure whereby fluid is trapped in the tube between said closure points, pressure means for pressing said tube between said closure points whereby fluid is forced through said yieldable closure means and single means for operating directly both said pressure and second closure means only.

4. Fluid transfer apparatus. comprising a flexible tube, spaced guide blocks adapted to receive said flexible tube adjacentthereto, a yieldable tube closure block movably mounted on one of said guide blocks, a power lever arm pivotally mounted adjacent the other guide block, a

second closure blockattached to said arm and movable adjacent the other guide block into tube closure position to trap fluid in a section of tube between said closure blocks, and means operable by-said arm to compress the tube between the closure blocks whereb trapped fluid is forced by said yieldable closure block, said means being adjustable to permit variation in the speed of flow of fluid delivered.

5. Fluid transfer apparatus, comprising spaced guide blocks adapted to receive a flexible tube adjacent thereto, a yieldable tube closure block movably mounted on one of said guide blocks, a power lever arm pivotally mounted adjacent the other guide block, a second closure block attached to said arm and movable adjacent the other guide block into tube closure position to trap fluid in a section of tube between said closure blocks, and means operable by said arm and in direct contact with said tube to compress the tube between the closure blocks whereby trapped-fluid is forced by said yieldable closure block, said second closure block functioning to close the tube after the first closure block and before the compression means.

6. Fluid transfer apparatus comprising a flexible tube for conducting a fluid, first means for maintaining said tube yieldably closed at a predetermined point, second means for closing said tube at a point displaced from the first closure point whereby fluid is trapped in the tube between said closure points, automatic pressure means for pressing said tube between said closure points whereby fluid is forced through said yieldable closure, and means for controlling separately the actuation rate of said pressure and second means.

7. Fluid transfer apparatus comprising a flexible tube for conducting a-fluid. first means for maintaining said tube normally closed at a predetermined point, second means for closing said tube at a normally open and unrestricted point displaced from the first closure point whereby fluid is trapped in the tube between said closure points, pressure means for pressing said tube between said closure points, and automatic means for actuating said second and pressure means intermittently whereby fluid is forced through said yieldable closure.

8. Fluid transfer apparatus comprising a flex ible tube for conducting a fluid, first means for maintaining said tube normally closed at a predetermined point, second means for closing said tube at a point displaced from the first closure point whereby fluid is trapped in the tube between said closure points, pressure means in direct physical engagement with said tube for pressing said tube between said closure points, and single means for actuating directly and only said second and pressure means intermittently whereby fluid is forced through said yieldable I 

